Abstract

This paper proposes and discusses an approach for the design and quality inspection of the morphology dedicated for sound absorbing foams, using a relatively simple technique for a random generation of periodic microstructures representative for open-cell foams with spherical pores. The design is controlled by a few parameters, namely, the total open porosity and the average pore size, as well as the standard deviation of pore size. These design parameters are set up exactly and independently, however, the setting of the standard deviation of pore sizes requires some number of pores in the representative volume element (RVE); this number is a procedure parameter. Another pore structure parameter which may be indirectly affected is the average size of windows linking the pores, however, it is in fact weakly controlled by the maximal pore-penetration factor, and moreover, it depends on the porosity and pore size. The proposed methodology for testing microstructure-designs of sound absorbing porous media applies the multi-scale modeling where some important transport parameters—responsible for sound propagation in a porous medium—are calculated from microstructure using the generated RVE, in order to estimate the sound velocity and absorption of such a designed material.

This work was carried out in part using computing resources of the “GRAFEN” supercomputing cluster at the IPPT PAN, from the computer infrastructure of Biocentrum Ochota. Finite element calculations were effectuated using the COMSOL Multiphysics software at the IPPT PAN, funded in part from the Structural Funds in the Operational Programme—Innovative Economy (IE OP, Poland) financed from the European Regional Development Fund—the Project “Modern Material Technologies in Aerospace Industry,” No. POIG.0101.02-00-015/08. The author also wishes to thank Dr. Marek Potoczek from Rzeszów University of Technology for providing the ceramic material for the porous sample which served to produce the experimental curve presented in Fig. 20.